Liquid polyamide epoxy resin hardener

ABSTRACT

wherein R3 and R4 are H or alkyl having 1-19 carbon atoms), or the dibasic acid prepared by hydrolysis of said ester, or the saturated dibasic acid or ester prepared by hydrogenation of said acid or ester, with (B) polyalkylene polyamine.   An epoxy resin hardener consisting of polyamide resin prepared by reacting (A) dibasic acid ester of the formula, R2OOC-CH2-CH2R1-CH2-CH2-COOR2 (wherein R1 is a bivalent vinylidene-type olefin radical having one double bond and R2 is a radical which forms an ester with acrylic acid), which dibasic acid ester is prepared from acrylic ester and vinylidene type olefin

United States Patent [WI Asai et al.

| LIQUID POLYAMIDE EPOXY RESIN HARDENER [75] Inventors: Schumkichiro Asai: Yasuyuki Kawakatsu. both ol Waka \ama. Japan [73! Assignee' Kan Snap 0).. Ltd.. Tok \o. Japan [22] Filed: Dec. 2|. I973 [3| 1 Appl. No; 427.081

[30] Foreign Application Priorit Data Dec, 17. W72 Japan 4 4%- [52] [.S. 260/[8 PX: lfillilfi N; 26ml} R; 260/23 EPZ INN-l7 EP'. IOU/73 R. 260/78 L A; 260, '830 P [51 Int. Cl. V t C080 59744 [58} Field of Search 360/18 N. l8 PN. 78 R. 36U/73 CA. 486 R. I R. 23 EP. 830 P l56] References Cited UNITED STATES PATENTS 2.l74.6l- I HlU ('arothers 16(1778 3.282.872 l7|966 Balles et a1 7.. Itwllfills 3.497.479 1.01970 Cassar Z6llf7$ 3.63755! NW7: Sprauer V 36W 3.647.765 NW7: Uortillaro et al. .h I6W7h 3.783136 li'| )7-l lnultai et al 36%486 3.i ll3.llll 4J'l974 Whilon. 260718 llll 3,919,142

Nil lElov. I}, 1975 FOREIGN PATENTS OR APPLICATIONS SMASH 81%| L'nited Kingdom xlIIUIIlLY. .temr. or Firm-Woodhams. Blanchard and Hum [57} ABSTRACT An epox resin hardener consisting of polyamide resin prepared h reacting (A) dibasie acid ester of the formulav oot 411 R.(H;-(H .*("()()R; (wherein R, is a liimlent \in \'lidene-t)pe olefin radical liming one double bond and R is a radical which forms an ester \rith aer \lic acid). which dihasic acid ester is prepared from acrylic ester and \inylidene t pe olel'ln wherein R. and R, are H or a|k \l having l-l9 carbon atoms). or the dibasic acid prepared h hydrolysis of said ester. or the saturated dihasic acid or ester prepared b lndrogenation of said acid or ester. with (B) po| a|k \lene polyamine.

9 Claims. N0 Drawings LIQUID POLYAMIDE EPOXY RESIN HARDENER BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an epoxy resin hardener prepared by a condensation reaction between polyalkylene polyamine and dibasic acid ester produced by reaction of acrylic acid ester and vinylidene type olefin in the presence of an acid catalyst, or the dibasic acid prepared by hydrolysis of the ester, using polymerized fatty acid or monobasic acid as modifier, if necessary.

2. Description of the Prior Art A known polyarnide resin which has been used as an epoxy resin hardener is a viscous liquid prepared by reacting polymerized fatty acid with an aliphatic polyamine. A modifier such as a monobasic acid, can be employed if necessary. This prior art polyamide hardener for epoxy resins has the advantages that it can be used for hardening at room temperature, it produces flexible products, it is less toxic, and it has a long potlife. But it also has significant disadvantages. For instance, the hardened product is unsatisfactory in acid resistance and solvent resistance and also has insufficient adhesion strength.

SUMMARY OF THE INVENTION We have discovered that a novel polyarnide resin having improved properties as an epoxy resin hardener, can be prepared by replacing part or all, that is, 100-50 mole of the polymerized fatty acid such as dimeric acids having 32 to 44 carbon atoms, conventionally used to make polyarnide resin useful as epoxy resin hardener, with a special dibasic acid ester which is a reaction product of acrylic acid ester and vinylidene type olefin, or the dibasic acid obtained by hydrolysis of the corresponding ester or the corresponding saturated acid or ester compounds.

The dibasic acid compound employed as a starting reactant for preparing the polyamides, according to the invention, has the formula R|OOCCH,-CH,R,--CH,CH,-COOR, I

wherein R, is a bivalent hydrocarbon radical of the formula (in these formulas, the double bond may be moved to a position other than those illustrated therein) wherein R, and R,, which can be the same or differcm, are H or alkyl having 1 to 19 carbon atoms,

R, is H or a radical which forms an ester with acrylic acid.

The dibasic acid compound employed in this invention, Formula l, thus includes both unsaturated esters and acids and saturated esters and acids. The unsaturated dibasic acid ester is prepared first. If desired, it can be converted to the corresponding acid and to the corresponding saturated ester or acid by conventional hydrolysis and hydrogenation procedures or combinations of such procedures.

The ester moiety R when R, is a radical which forms an ester with acrylic acid, is not critical and it can be derived from compounds which are reactive with acrylic acid to form acrylic acid esters. [t is preferred, however, that R, is selected from the group consisting of alkyl having I to 8 carbon atoms such as methyl, ethyl, propyl and butyl, alkenyl having 2 to 8 carbon atoms, such as allyl, cycloalkyl having 3 to 8 carbon atoms, such as cyclohexyl, cycloalkenyl having 3 to 8 carbon atoms, and aryl and aralkyl having up to 8 carbon atoms such as benzyl. It is especially preferred that R, is methyl.

It is preferred that one of R and R, is H and the other is CCH,

The starting dibasic acid ester of Formula I, wherein R, is an ester moiety, used in this invention is prepared as follows: 0.1 to 2 mols of vinylidene type olefin such as diisobutylene and 1 mol of acrylic acid ester are heated to react in the presence of an acid catalyst such as aluminum chloride. The catalyst is removed by a conventional process such as water-washing. There is obtained a mixture containing two reaction products, in which the molar ratios of the acrylic acid ester moiety: vinylidene type olefin moiety are 1:] and 2:1, respectively. From the reaction product mixture, the l:l reaction product (monobasic ester) is distilled off under reduced pressure to obtain the desired dibasic acid ester starting material. This dibasic acid ester has the following general formula:

R, ooc-cH,-ct-l,-R, CH,-CH-

,-cooa,

wherein R, and R, are as defined above. The preparation of such starting dibasic acid ester is disclosed in the pending US. patent application Ser. No. 298,3 89, now abandoned of Ueda et al.

In the present invention, in the polyamidation reaction described below, in addition to the abovedescribed dibasic acid ester there can be used the corresponding dibasic acid prepared by conventional hydrolysis of said dibasic acid ester, or the corresponding saturated dibasic acid or its ester prepared by a conventional hydrogenation of the double bond of R, in the formula IV dibasic acid ester.

For producing an epoxy resin hardener consisting of polyamide resin, according to this invention, a conventional polyamidation reaction can be employed in accordance with known procedures. The reaction temperature is from 1 to 350C, preferably from 170 to 280C and the reaction time is from I to 10 hours. An acidic catalyst, such as the conventional phosphoric acid catalyst, can be used during the reaction, but the reaction can be performed without using a catalyst. it is preferred to perform the polyamidation reaction in an inert gas atmosphere such as nitrogen gas to prevent coloring of the reaction product. If desired, the reaction can be carried out under reduced pressure for accelerating the reaction.

As the polyamine to be used as a reactant in the polyamidation reaction, there are used aliphatic polyalkylene polyamines of the formula H,N(CH,CH,NH),,H wherein n is an integer of from 1 to 5. Ethylenediamine, diethylenetriamine, triethylenetetramine and tetraethylene pentamine are preferred. It is also acceptable to use in combination with said aliphatic polyalkylene polyamines, up to 50% by weight, based on the total weight of polyamines, of aromatic polyamines such as phenylene diamine and xylylene diamine and alicyclic polyamines such as cyclohexane diamine and isophorone diamine to modify the properties of the polyamide resin product.

For controlling the molecular weight of the polyamide resin product of this invention, a monobasic acid can be used in the polyamidation reaction, if necessary. As the monobasic acid, there can be used any fatty acid of saturated, unsaturated, long-chain and branched type, such as fatty acids RCOOH in which R is an aliphatic hydrocarbon radical having 9 to 23 carbon atoms and mixtures thereof. Particularly fatty acids and mixtures thereof occurring in oils of natural products such as fatty acids of soybean oil, cottonseed oil or rape seed oil are preferred. Of course, there can also be used aromatic acids such as benzoic acid and salicyclic acid, alicyclic acids such as cyclohexane carboxylic acid, and naphthenic acid, and oxy acids such as castor oil fatty acid and hydroxystearic acid, and mixtures thereof.

In producing the polyamide resin of this invention, the ratio of carboxyl equivalent to amine equivalent of the reactants is not particularly limited as long as gelation is avoided. In general a ratio of carboxyl equivalentzamine equivalent in the range of from 1:12 to 1:5 is preferred.

in producing the polyamide resin of this invention, the ratio of dibasic acid and monobasic acid in the reactant mixture can be optionally selected depending on the desired molecular weight of the polyamide resin product. However, it is preferable to use monobasic acid in an amount of less than 2 equivalents, more preferably less than 1 equivalent, per 1 equivalent of dibasic acid. The polyamide resin of the present invention has a molecular weight of 400 to 2,000. [f the molecular weight is larger than 2,000 the resin will be a solid and not suitable as a hardener for epoxy resins.

The polyamide resin product according to this invention can be employed as a hardener for epoxy resins in accordance with conventional practice. As is well known, the epoxy resins are polyepoxides possessing more than one of vicepoxy group, i.e., more than one groups. The polyepoxides can be saturated or unsaturated, aliphatic, cycloaliphatic, aromatic or heterocyclic and can be substituted if desired with substituents, such as chlorine atoms, hydroxyl groups, ether radicals and the like. They can also be monomeric or polymeric.

The polyepoxide compounds to be used in the present invention include diglycidyl ethers of bisphenol A, dicyclopentadiene dioxide, diglycidyl ethers of dimer alcohols and the like. Among such polyepoxides, the most preferred are diglycidyl ethers of bisphenol A obtained by reacting 2,2-bis(4-hydroxyphenyl)-propane with epichlorohydrin in an alkaline medium, which have already been placed on the market as a typical polyepoxide.

Typical commercially available epoxy resins are Epicoat 815, 828 and 834 (all liquids) and Epicoat 1001 and 1004 (solids), all of which are products of Shell Oil Company. Other glycidyl epoxy resins can of course be employed.

The amount of polyepoxide and hardener in the composition can vary depending on the properties desired in the resulting products. The polyepoxide and hardener are combined in a weight ratio in the range of 10:1 to 1:10. It is preferred to employ a weight ratio of polyepoxidezhardener in the range of from 1:2 to 110.1.

Usual modifiers, such as extenders, fillers, reinforcing agents, color agents, organic solvents, plasticizers and the like can be present in the curable composition.

The invention is further described by reference to the following illustrative, non-limiting Examples.

EXAMPLES 1 TO 9 AND COMPARISON EXAMPLES 1 AND 2 73 Kg. of methyl acrylate, 42 kg. of diisobutylene, and 7.3 kg. of aluminum chloride, as a catalyst, were placed in a glass-lined vessel provided with a stirrer, a thermostat and a reflux condenser, and they were reacted at the reflux temperature for 15 hours. The reaction mixture was neutralized with caustic soda aqueous solution. Then the unreacted methyl acrylate and water were distilled off under reduced pressure. Then, 33.2 kg. of 25% sulfuric acid aqueous solution were added to convert the aluminum chloride to aluminum sulfate, and the mixture was water-washed to remove the catalyst until the washings became neutral. There was obtained kg. of crude dibasic acid methyl ester. From the crude dibasic acid methyl ester, 18.5 kg. of the byproduced monobasic acid methyl ester were distilled off under reduced pressure and there was obtained 81.5 kg. of purified dibasic acid methyl ester (acid value, 21.3:saponification value, 387.3: iodine value, 79.6).

This dibasic acid methyl ester is a mixture of the compound of the formula of and the compound of the formula of in a ratio of about 1:!

The thus-obtained dibasic acid methyl ester, oleic acid, and polyamine were charged into a reactor provided with a stirrer, a thermostat, a cooling dehydrating was hydrogenated in an autoclave with a palladiumcarbon catalyst to produce saturated dibasic acid methyl ester (saponification value, 4l6.5; iodine value, 0.7). With the resulting ester, the reaction was carried tube and a nitrogen blower, and then, were heated up 5 out by the same process as in Examples I-9. The folgradually to 220C during which time water and methalowing Table II shows the reactants for the syntheses Table ll Properties of Polyamidc Example Saturated Monobasic Triethylene- Total amine Viscosity,

dibasic acid acid methyl tetramine value c.p. methyl ester ester by- (40C) product I0 2000g Il68g are I8600 I I 2000 400g I lllg 209 36500 nol were distilled off. After reacting the materials at a and the properties of the resultant polyamides. temperature of 220C for 2 hours, the temperature was EXAMPLE 2 further elevated from 220 to 270C, the reaction was continued at the latter temperature for 4 hours, and An epoxy resin (Epicoat 828, a trademark of Shell after cooling,apolyamide resin was obtained. For com C0,) was hardened with the hardeners of polyamide parison, polyamide resins were similarly produced emresins which were prepared in Examples 1-1 1 and ploying polymerized fatty acid instead of dibasic acid Comparison Example 1-2. The chemical resistance and methyl ester as in Examples 1 to 9. g the adhesion strength of the hardened resin were The following Table 1 shows the reactants for the vartested. In the test, 100 parts of the epoxy resin and the ious syntheses and the properties of the resulting polyhardener shown in the following table were well mixed amides. in a breaker. the mixture was applied to a glass plate for Table 1 Properties of Polyamide Example Dibasic Acid Oleic Polyamine Total amine Viscosity, Methyl Ester acid value 25C, c.pv

I 72l g I395 g Triethylenetetram'me I267 g 400 792 2 72 l I395 Triethylenetetramine 852 244 8500 3 I441 698 Triethylenetetramine l I74 322 19800 4 72l I 39 S Diethylenetriamine I07I 325 860 5 I441 698 Diethylenetriamine 844 245 10400 6 I441 I39 5 Diethylenetriamine 94l 198 19000 7 I44I I395 Tetraethylene pentamine I938 4I0 9800 8 721 1395 Tetraethylene pentamine I201 350 3600 9 2000 Triethylenetetramine 967 250 97800 Comparison Polymerized Oleic Polyamine Total amine Viscosity, Example fatty acid acid value 25C, c.p.

I I087 g 337 Triethylenetetramine 77I 330 8400 2 I440 Tetraethylene pentamine 756 300 70000 Industrial oleic acid having an acid value of 200.4. a saponification value 01' 2010 and an iodine value of 872. "Empole I022 of Emery Co, (acid value. [94.8: snponification value. 1960; iodine value, 99.1)

EXAMPLES l0-ll The dibasic acid methyl ester used in Examples l-9 Table III Polyamide Amount of polyamide Chemical resistance Adhesion, resin resin added per I00 kg/cm parts of Epicoat 828 Acid Solvent Example I 45 parts Unchanged Unchanged I22 2 90 parts Unchanged Unchanged I35 3 parts Unchanged Unchanged I37 4 60 parts Unchanged Unchanged I48 5 90 parts Unchanged Unchanged I 6 I I0 parts Unchanged Unchanged I 7 40 parts Unchanged Unchanged I58 8 60 parts Unchanged Unchanged I69 9 60 parts Unchanged Unchanged I76 I0 60 parts Unchanged Unchanged I51 I I 60 parts Unchanged Unchanged I64 Comparison Example I 60 parts Changed to Swollen brown 96 2 60 parts Changed to Swollen I04 brown and a little swollen applied to a glass plate with an appiicator to form a layer of 50p. thickness.

1 day at room temperature 7 days at room temperature 50% sulfuric acid aqueous solution Chemical resistance test:

Application conditions;

Hardening conditions:

lmmersing time: Acid resistance:

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

l. A liquid polyamide resin, useful as an epoxy resin hardener. consisting essentially of the reaction product of a carboxylic acid or ester reactant and a polyamine reactant, reacted at a ratio of carboxyl equivalents to amine equivalents of from 1:1.2 to 1:5.0, at 110 to 350C, for from 1 to 10 hours, said reaction product having a molecular weight of from 400 to 2000, said carboxylic acid or ester reactant consisting essentially of A. a dibasic component consisting of 1. up to 50 mole of dimer acid having 32 to 44 carbon atoms, and 2. the balance is a compound or mixture of compounds having the formula R,o0c cit,-CH.-R.-CH,-c|-|,-Cooa, wherein R, has the formula wherein R and R which can be the same or different, are hydrogen or alkyl having I to 19 carbon atoms and R, is hydrogen or a radical which forms an ester with acrylic acid,

B. from zero to less than 2 equivalents, per one equivalent of the dibasic component A, of a monobasic acid capable of controlling the molecular weight of the polyamide product;

said polyamine reactant consisting essentially of 3. up to 50% by weight of a polyamine selected from the group consisting of aromatic polyamines and alicyciic polyamines, and 4. the balance is polyalkylene polyamine having the formula H,N(CH,CH,NH ),,H, wherein n is an integer of from 1 to 5.

2. A polyamide resin according to claim 1, in which one of R, and R. is hydrogen and the other thereof is s)a- 3. A polyamide resin according to claim 2, in which said polyalkylene polyamine is selected from the group consisting of diethylenetriamine, triethylenetetramine and tetraethylenepentamine.

4. A polyamide resin according to claim 3, in which said monobasic acid is a fatty acid or mixture of fatty acids having from 10 to 24 carbon atoms.

5. A polyamide resin according to claim 4, in which said dibasic component consists of A(2), and said polyamine component consists of said polyalkylene polyamine.

6. A cured epoxy resin composition obtained by reacting (a) a 1,2-polyepoxide compound having on the average more than one 1,2-epoxide group in the molecule, with (b) a polyamide as claimed in claim 1, as a curing agent, the weight ratio of (a) to (b) being in the range of from 10:1 to 1:10.

7. A composition according to claim 6, in which the weight ratio of (a) or (b) is from 1:2 to 120.1.

8. A process of curing a 1,2-polyepoxide compound having on the average more than one 1,2-epoxide group in the molecule, which comprises, incorporating in said 1,2-po1yepoxide compound, a polyamide as claimed in claim 1, as a curing agent, the weight ratio of said 1,2-polyepoxide compound to said polyamide being from 10:1 to 1:10.

9. A. process as claimed in claim 8 in which the weight ratio of said 1,2-polyepoxide compound to said polyamide is from 1:2 to 1:0.1. 

1. UP TO 50 MOLE % OF DIMER ACID HAVNG 32 TO 44 CARBON ATOMS, AND
 1. ALIQUID POLYAMIDE RESIN, USEFUL AS AN EPOXY RESIN HARDENER, CONSISTING ESSENTIALLY OF THE REACTION PRODUCT OF A CARBOXYLIC ACID OR ESTER REACTANT AND A POLYAMINE REACTANT, REACTED ZT A RATIO OF CARBOXYL EQUIVALENTS TO AMINE EQUIVALENTE OF FROM 1:1.2 TO 1:5.0, AT 110* TO 350*C, FOR FROM 1 TO 10 HOURS, SAID REACTION PRODUCT HAVING A MOLECULAR WEIGHT OF FROM 400 TO 2000, SAID CARBOXYLIC ACID OR ESTER RECTANT CONSISTING ESSENTIALLY OF A. A DIABASIC COMPONENT CONSISTING OF
 2. A polyamide resin according to claim 1, in which one of R3 and R4 is hydrogen and the other thereof is -C(CH3)3.
 2. the balance is a compound or mixture of compounds having the formula R2OOC-CH2-CH2-R1-CH2-CH2-COOR2 wherein R1 has the formula
 2. THE BALANCE IS A COMPOUND OR MIXTURE OF COMPOUNDS HAVING THE FORMULA R2OOC-CH2-CH2-R1-CH2-CH2-COOR2 WHEREIN R1 HAS THE FORMULA
 3. A polyamide resin according to claim 2, in which said polyalkylene polyamine is selected from the group consisting of diethylenetriamine, triethylenetetramine and tetraethylenepentamine.
 3. UP TO 50% BY WEIGHT OF A POLYAMINE SELECTED FROM THE GROUP CONSISTING OF AROMATIC POLYAMINES AND ALICYCLIC POLYAMINES, AND
 3. up to 50% by weight of a polyamine selected from the group consisting of aromatic polyamines and alicyclic polyamines, and
 4. THE BALANCE IS POLYALKYLENE POLYAMINE HAVING THE FORMULA H2N(CH2CH2NH)NH, WHEREIN N IS AN INTEGER OF FROM 1 TO
 5. 4. the balance is polyalkylene polyamine having the formula H2N(CH2CH2NH)nH, wherein n is an integer of from 1 to
 5. 4. A polyamide resin according to claim 3, in which said monobasic acid is a fatty acid or mixture of fatty acids having from 10 to 24 carbon atoms.
 5. A polyamide resin according to claim 4, in which said dibasic component consists of A(2), and said polyamine component consists of said polyalkylene polyamine.
 6. A cured epoxy resin composition obtained by reacting (a) a 1, 2-polyepoxide compound having on the average more than one 1,2-epoxide group in the molecule, with (b) a polyamide as claimed in claim 1, as a curing agent, the weight ratio of (a) to (b) being in the range of from 10:1 to 1:10.
 7. A composition according to claim 6, in which the weight ratio of (a) or (b) is from 1:2 to 1:0.1.
 8. A process of curing a 1,2-polyepoxide compound having on the average more than one 1,2-epoxide group in the molecule, which comprises, incorporating in said 1,2-polyepoxide compound, a polyamide as claimed in claim 1, as a curing agent, the weight ratio of said 1,2-polyepoxide compound to said polyamide being from 10:1 to 1:10.
 9. A process as claimed in claim 8 in which the weight ratio of said 1,2-polyepoxide compound to said polyamide is from 1:2 to 1: 0.1. 